Dehydration can occur quickly in young children and should be monitored closely. The main signs of dehydration in children are:

• Lethargy (less than normal activity)
• Irritability
• Decreased frequency of urination or dry diapers
• Absence of tears when the child cries
• Sunken eyes
• Sunken fontanel (the soft spot on the top of the head in babies)
• Dry or sticky mucous membranes